Former New York City mayor and major political donor Michael Bloomberg has taken a step toward running for president in 2020 by re-registering as a Democrat, he shared on social media Wednesday.

“At key points in U.S. history, one of the two parties has served as a bulwark against those who threaten our Constitution,” Bloomberg wrote on Instagram. “Two years ago at the Democratic Convention, I warned of those threats. Today, I have re-registered as a Democrat – I had been a member for most of my life – because we need Democrats to provide the checks and balance our nation so badly needs.”

By registering as a Democrat, former Independent Bloomberg could avoid the hassle of complicated filings that the 2016 Bernie Sanders campaign went through when the Vermont senator planned to decline the Democratic nomination if he received it and run as an Independent, reported Politico.

Bloomberg was a “longtime Democrat” before leaving the party in 2001 to be elected as the Republican mayor of New York City that same year, according to Ballotpedia. However, he has recently donated large sums to pro-Democratic groups, including “$20 million that will go to the Senate Majority PAC, empowered to elect Democrats to the Senate,” reported The Daily Caller on Oct. 3.

Bloomberg has been registered as a Republican, Independent and Democrat and has held office as a Republican. He was elected New York City mayor in 2001, 2005 and 2009 as the Republican candidate even though he switched to an Independent in 2007, according to Ballotpedia.

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